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Claims Held Invalid for Failing to Include the Best Mode Within the Specification

Although allegations of a patentee’s failure to disclose the best mode of a claimed invention rarely succeed in rendering asserted claims of a patent invalid, the Federal Circuit recently affirmed in Ajinomoto Co., Inc. v. International Trade Commissiona determination of invalidity by the U.S. International Trade Commission (ITC) that should alert patent practitioners and inventors of the importance of disclosing the preferred mode of practicing an invention. In accordance with U.S. patent rules and as highlighted by this case, in drafting a patent application, practitioners should inquire, and inventors should disclose, if there is a preferred embodiment of a claimed invention or any other preferences that materially affect the properties of the invention.

In this case, Ajinomoto Co., Inc. (Ajinomoto) filed a complaint with the ITC alleging that Global Bio-Chem Technology Group (GBT) violated 19 U.S.C. § 1337 by importing into the United States animal feed products containing an amino acid produced by a method which infringes various claims of U.S. Patent No. 5,827,698 (“the ‘698 patent”) and U.S. Patent No. 6,040,160 (“the ‘160 patent”). Each of the asserted claims at issue recited methods that included cultivating an E. coli type bacteria having a specific genetic mutation to provide increased lysine production.

Before the Administrative Law Judge (ALJ) at the ITC, GBT admitted infringement of the claimed methods, but argued that the asserted claims were invalid because Ajinomoto’s specification failed to disclose the best mode of the invention as required by 35 U.S.C. § 112, first paragraph. GBT further argued that the patents at issue were unenforceable due to Ajinomoto’s inequitable conduct in not only failing to disclose the best mode, but also in affirmatively concealing the preferred bacterial strains and carbon sources and submitting fictitious data in support of the best mode. The ALJ agreed with GBT and found no violation of § 1337 because the asserted claims were invalid and the ‘698 and ‘160 patents were unenforceable. Ajinomoto unsuccessfully petitioned the Commission for review of the ALJ’s determination and subsequently appealed to the Federal Circuit.

35 U.S.C. § 112, first paragraph, requires that a patent specification “set forth the best mode contemplated by the inventor of carrying out his invention.” In order to satisfy the best mode requirement, an inventor must disclose the preferred embodiment of the invention defined by the claims as well as preferences that materially affect the properties of the invention. In a best mode inquiry, a court first defines the invention by construing the claims and then determines whether the inventor contemplated a best mode of practicing the claimed invention at the time of filing the application. If the inventor had a subjective preference for one mode over others, the court must then determine whether the specification’s disclosure was sufficient to allow one of ordinary skill in the art to practice the best mode of the invention.

Ajinomoto admitted before the Federal Circuit that the inventors had a preferred strain, which contained additional non-claimed genetic mutations, for producing lysine in culture, as well as a preferred carbon source within the culture medium. Nonetheless, Ajinomoto argued that the ITC erred in analyzing whether the best mode of the invention was disclosed by focusing on the “overall production of lysine,” rather than on the “innovative aspects” of the specific genetic mutations that were claimed. The Federal Circuit affirmed the ITC’s reasoning that the scope of the invention as defined by the claims covers more than the specifically-recited mutations. Indeed, because the claimed invention recites “cultivating” a bacterial host strain containing those mutations, the failure to disclose the preferred strains and carbon sources used in the cultivation process renders the asserted claims invalid for failure to disclose the best mode of practicing the claimed invention.

Although it is not necessary to label a preferred embodiment as the “best mode” within a patent specification, Ajinomoto v. ITC provides a strong reminder of the importance of providing an enabling disclosure for a preferred embodiment, as contemplated by the inventors at the time of filing of an application. Practitioners should also note that in analyzing whether the specification discloses the best mode, courts will consider all of the limitations of the claimed invention, rather than just the “novel” features that distinguish the claim over the prior art.

The Federal Circuit declined to review the ITC’s determination that the ‘698 patent and the ‘160 patent were unenforceable due to Ajinomoto’s inequitable conduct. Ajinomoto’s only contention on appeal was a single sentence that the decision on inequitable conduct should be reversed because it was based on erroneous conclusions regarding Ajinomoto’s failure to disclose the best mode. The Federal Circuit concluded that “[s]uch a conclusory assertion unaccompanied by developed argumentation does not preserve the issue for appeal.”

This advisory was prepared by Nutter's Intellectual Property practice. For more information, please contact your Nutter attorney at 617-439-2000.

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